Sodium chloride is #NaCl#, and sodium sulfide is #Na_2S#. Why are there more sodium ions in the sulfide compound?

1 Answer
Jul 1, 2016

Answer:

To give electric neutrality.

Explanation:

Sodium chloride is composed of #Na^+# ions and #Cl^-# ions. Now of course salt is neutral; and to ensure this sodium ion and chloride ions combine 1:1.

On the other hand, sulfur commonly forms an #S^(2-)# ion. (Sulfur is a #"Group VI"# atom, and its chemistry is similar to oxygen, which certainly forms the #O^(2-)", oxide"# ion.) Since sodium sulfide is a neutral salt, each sulfide ion requires #2xxNa^+# ions. Capisce?

Why are there #3# sodium atoms in #Na_3P#?